Monitor, a public body sponsored by the Department of Health, published its report just weeks after a delay in the merger was announced. It considered the likely improvements to care, patient experience and patient outcomes to be clinically significant and of high importance to patients.

Particularly, it noted extended access to consultant-led care in gastroenterology, stroke and interventional radiology services should be taken into account as benefits.

“Improved access to a consultant out of hours and at weekends is a clinically significant service improvement in these specialities, each of which provides emergency care for acutely ill patients”, the report states.

“It is our view that extended access to consultant- led care in gastroenterology would result in an improvement for about 300 emergency patients per year who present with life-threatening problems, by providing a stable and formal rota out of hours and at weekends.

“Some of these patients are currently transferred to another hospital or have to wait until the following Monday for treatment because a consultant is not available when they arrive at hospital”.

The report will also provide advice to the Competition and Markets Authority (CMA), which is investigating the merger.

If the CMA concludes there will be a reduction, it will take Monitor’s advice into account when considering whether the relevant patient benefits outweigh the reduction in competition and patient choice.

Monitor has ruled out some of the benefits proposed by the hospitals.

For instance, it found that extended access to a consultant neurologist could be achieved in a timely way without the merger.

“In our view the parties have not demonstrated that the introduction of extended access to a specialist diabetes nurse, in addition to the five-day service already provided, would lead to a real improvement for patients”, the report says.

The chief executive of the Royal Surrey, Nick Moberly, said: “We are really pleased that Monitor has endorsed many of the patient benefits which would result from our proposed merger.

“Very importantly, they have recognised the value to patients of extending access to consultant-led care in gastroenterology, stroke and interventional radiology out of hours and at weekends, and that this would be a significant improvement for patients who are acutely ill.

“This is something we aren’t able to do currently, and is one of the reasons we believe merger is the best way forward for patients.”

Suzanne Rankin, chief executive of Ashford and St Peter’s Hospitals, said: “Of course there are other, wider benefits of merging our two foundation trusts, such as creating the platform for clinical and financial sustainability of our two organisations, future opportunities to develop the range of specialist services we offer as well as being able to attract and retain the very best staff.

“While these benefits are more difficult to quantify at this stage, we still believe the merger would benefit patients and staff in many different ways, helping us to continue to invest in and develop the very best healthcare services for local patients.”

The CMA is expected to conclude its investigation within the next six months.